Polar Vortex in Summer? Not Exactly, Experts Say

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A blast of cold air that blew in from the Gulf of Alaska and
swept across the Great Lakes is now making its way south.
Headlines warn that the cold front could herald a return of the
"polar vortex," but experts are saying otherwise.

Polar vortexes typically develop around the North Pole
during most winters. They form in a pattern similar to that of
tropical hurricanes, except the winds spinning around the calm
center of a polar vortex are freezing cold.

In January, a
polar vortex blasted the northern United States with frigid
air and caused bitterly cold temperatures farther south than
normal. This week's cold front is following a similar pattern,
where cold air from the Arctic is sweeping down south. [ Weirdo
Weather: 7 Rare Weather Events ]

Typhoon
Neoguri, which battered southern Japan with strong wind and
rains last week, likely set off the wacky weather pattern that is
interfering with the jet stream over the Midwest. TheMidwestern
jet stream is a strip of air that forms when cool air masses from
the north meet warm air masses from the south. An unusual amount
of cold air can drive the jet stream further south and trigger
thunderstorms.

By this Wednesday (July 16), the unusual weather could turn what
is normally one of the hottest weeks of the summer into a
pleasant autumnlike week in parts of the western United States
and Northern Plains, where highs may be about 65 to 70 degrees
Fahrenheit (18 to 21 degrees Celsius). The cold front will likely
deal the Northeast only a glancing blow, and temperatures in this
region may dip about 10 degrees below average.

Strictly speaking, the cold front is not a polar vortex,
according to experts. The impending cold front is called a "high
meridional event," but there are some similarities.

"It's the same general
circulation pattern, but the effects are extremely
different," Bob Oravec, a senior forecaster at the National
Oceanic and Atmosphere Administration (NOAA) Weather Prediction
Center, told Live Science. "In the summer, if you go outside in
20 degrees (Fahrenheit) below normal weather, you won't really
care, but in the winter, the effects were significantly different
because it was already so cold."

NOAA is predicting below-normal temperatures for a huge swath of
the East Coast this week. The cool air is expected to roll
through tomorrow (July 15), and should keep temperatures between
70 and 80 degrees Fahrenheit (21 to 27 degrees Celsius) on the
East Coast.

The unusual summer chill could also trigger some extreme and
dangerous weather in the United States, experts say. The cold
temperatures will likely send thunderstorms sweeping across much
of the country this week. Hail and tornadoes are possible in
southern New England down to the mid-Atlantic. In the West,
severe lightning, flash floods and dust storms are possible,
according to the Weather
Channel.

Despite the wild weather in store for this week, Oravec said the
cold front could bring some significant benefits. The predicted
downpour may finally quench the severe drought in the western
United States. While parts of the country may welcome a change
from the sweltering July heat, temperatures are expected to climb
back up soon.